1. Field of the Invention
The invention concerns the manufacturing of chip cards, particularly cards capable of operating without contact by means of an antenna integrated into the card. Under this name xe2x80x9ccontactless cardsxe2x80x9d, there are envisaged on the one hand cards which can communicate with the outside only through the antenna, and also and in particular mixed cards which can communicate with the outside either by means of the antenna or by means of standardised conventional contacts.
Such cards are intended to perform various operations such as, for example, banking operations, telephone communications, identification operations, operations of debiting or reloading units of account, all kinds of operations which can be performed either by inserting the card into a reader or remotely by electromagnetic coupling (in principle of the inductive type) between a sending/receiving terminal and a card placed in the zone of action of this terminal.
2. Related Background
Contactless cards must preferably have standardised dimensions identical to those of conventional smart cards provided with contacts. This is obviously particularly essential for mixed cards, and is desirable for cards operating solely without contacts.
The usual standard ISO 7810 defines a card 85 mm long, 54 mm wide and 0.76 mm thick. The contacts are flush at clearly defined positions on the surface of the card.
These standards impose severe constraints in manufacture. The very small thickness of the card is in particular a major constraint, more severe still for contactless cards than for cards simply provided with contacts, since it is necessary to provide for the incorporation of an antenna in the card.
The technical problems which are posed are problems of positioning the antenna with respect to the card, since the antenna occupies almost an entire surface of the card, problems of positioning the integrated-circuit module (comprising the chip and its contacts, which provides the electronic functioning of the card), and problems of precision and reliability of the connection between the module and the antenna; finally, constraints of mechanical strength, reliability and manufacturing cost must be taken into account.
The aim of the invention is to propose a manufacturing method which best resolves the different constraints of sizing, manufacturing precision, mechanical strength, and more generally reliability, cost and efficiency in manufacturing the card.
For this purpose, according to the invention, a method of manufacturing a chip card with contactless transmission is proposed, principally characterised in that an integrated-circuit module and an antenna made from flat-wound wire is produced, the antenna ends are fixed to connection areas of the module, the antenna/module assembly is temporarily fixed against a plate made of plastics material having an opening which can serve as a housing for the module, another plate of plastics material is placed on the antenna/module assembly, and the two plates are connected, enclosing the antenna and module.
The temporary fixing of the antenna/module assembly is preferably effected by bonding an adhesive sheet to the first plate and the module is applied against the adhesive face of this sheet inside the opening which serves as a housing for the module. The adhesive sheet is subsequently detached. If the card is a mixed card, the access contacts are bared when the sheet is removed, since they are flush with the bottom of the opening serving as a housing for the module.
This method is simple and inexpensive and reliably and precisely resolves the problem of contact between the chip module and the antenna: the electrical connection is made before fitting the assembly in a plastic card. The module is correctly placed in the card, and the antenna also.
The plastic film provided with metallic parts, on which the integrated circuit is placed in order to constitute the module, can in practice be in particular of two kinds: double-face printed-circuit film or metallic grille covered with an insulated plastic film, but in practice the solution with a double-face printed-circuit film is clearly preferably since it makes it possible to fix the antenna ends exactly flat on the connection areas, whilst the other solution would make it necessary to fix the antenna ends in insulating-film openings, the thickness of the insulating film around these openings impeding the fixing.
In the case of a module produced from a double-face printed circuit, the chip is fixed on one side (the front face of the film) and connected by soldered wires to metallic connection areas situated on this side. The antenna is also welded to connection areas on this side. The rear face has metallic parts cropped to the format of the standardised contacts of a smart card (for a mixed card), conductive vias being provided between the metallic parts of the front face and those of the rear face in order to establish the necessary electrical connections between the external contacts of the rear face and the inputs/outputs of the chip.
Conventionally, the chip is immersed in a protective resin before the module is inserted in the card.
The two plates of plastics material of the card can be connected by hot or cold lamination, a resin being able to be interposed between the two plates, in order to serve as a binder between them and as a sealing product in order to isolate the module and antenna from the outside.
In practice, the manufacturing method includes the following steps:
there is produced an integrated-circuit module which can be inserted in a card, comprising an integrated-circuit chip mounted on a plastic film provided with metallic parts, the metallic parts comprising on the one hand connection areas allowing a connection with the chip and on the other hand two connection areas for connection with an antenna, these two latter areas being at a given distance from each other and also being connected electrically to connection areas permitting connection with the chip;
a flat-wound antenna wire is produced, having two ends situated substantially at the same predetermined distance from each other;
the antenna ends are fixed to the two corresponding connection areas;
the antenna/module assembly is bonded against a plate made of plastics material having an opening which can serve as a housing for the module, so that the antenna/module assembly is held in place against the plate during the subsequent operations;
another plate made of plastics material is placed on the antenna/module assembly;
the two plates are connected, enclosing the antenna and module.